This invention relates generally to grapevine grooming and more particularly concerns apparatus for combing grape vines trained to a divided canopy system.
Grape vines which have a drooping growth habit benefit from shoot positioning to render the vines more active photosynthetically and to allow penetration of light into the fruit zone and the lower buds. Increasing the light that penetrates into the vine canopy improves fruit quality in the initial year of shoot positioning and makes the basel buds that receive the increased light intensity more productive for the following year.
Manual shoot positioning is impractical due to the cost and the difficulty in obtaining adequate hand labor to accomplish the task in a timely manner. Today, grapes with a drooping growth habit are usually trained either on a bilateral cordon or on a divided canopy trellis system. On a bilateral cordon system, the vines are trained to a single wire trellis. On a divided canopy system, or Geneva Double Curtain System, the vines are trained on two parallel wires mounted on cross arms attached to posts.
The divided canopy system will manage a vineyard that has more growth and production capacity than a bilateral cordon system because a single row of vines is trained into two rows. However, unless vines trained to a divided canopy system are shoot positioned, the growth and production advantages are lost due to the excess shading of the fruit, leaves and canes. An added benefit to shoot positioning is the facilitation of mechanical pruning which is only possible if a majority of the basel buds have adequate sunlight exposure, making hand selection unnecessary during the pruning process.
A machine with an overhanging arm with counter-rotating brushes disposed on opposites sides of the vines currently exists to shoot position vines trained to the single wire trellis of a bilateral cordon system. However, no satisfactory combing machine exists for use with the divided canopy system, which is the more productive and more desirable system for producing higher quality fruit. It has long been recognized that a machine with an underslung arm with counter rotating brushes could provide the necessary restraint to shoot position canes in a divided canopy system. However, no such machine has yet been developed that will work effectively because none will provide the necessary counter-rotating force on the horizontal portion of the vines extending from the posts to the cross arms and still allow the machine to move past the cross arms and crooked vine trunks of the divided canopy.
It is, therefore, an object of the present invention to provide a device for use with an underslung grape vine comber that will provide an upward counter-rotating force on the horizontal portion of vines extending horizontally in a divided canopy. It is a further object of this invention to provide such a brush that will pivot to clear the cross arms and crooked vine trunks of the divided canopy, as well as other immovable objects in its path, in response to contact of the brush with the cross arms, vine trunks or other immovable objects. Another object of the present invention is to provide such a counterforce brush apparatus as will permit variation of the angular disposition of the brush to accommodate various conditions of vine length, strength, entanglement and cleaning requirements. A further object of the present invention is to provide a counterforce brush usable on an underslung vine comber which may be mounted on a tractor, harvester or other suitable self-propelled farming equipment. And it is an object of the present invention to provide a counterforce brush usable with a variety of drive means, such as pneumatic, electrical or hydraulic, as may be convenient depending on the selected propelling apparatus as well as other limiting conditions.